/*
 * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
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 *
 *
 */

package javax.print;

import java.io.ByteArrayInputStream;
import java.io.CharArrayReader;
import java.io.StringReader;
import java.io.InputStream;
import java.io.IOException;
import java.io.Reader;
import javax.print.attribute.AttributeSetUtilities;
import javax.print.attribute.DocAttributeSet;

/**
 * This class is an implementation of interface <code>Doc</code> that can
 * be used in many common printing requests.
 * It can handle all of the presently defined "pre-defined" doc flavors
 * defined as static variables in the DocFlavor class.
 * <p>
 * In particular this class implements certain required semantics of the
 * Doc specification as follows:
 * <ul>
 * <li>constructs a stream for the service if requested and appropriate.
 * <li>ensures the same object is returned for each call on a method.
 * <li>ensures multiple threads can access the Doc
 * <li>performs some validation of that the data matches the doc flavor.
 * </ul>
 * Clients who want to re-use the doc object in other jobs,
 * or need a MultiDoc will not want to use this class.
 * <p>
 * If the print data is a stream, or a print job requests data as a
 * stream, then <code>SimpleDoc</code> does not monitor if the service
 * properly closes the stream after data transfer completion or job
 * termination.
 * Clients may prefer to use provide their own implementation of doc that
 * adds a listener to monitor job completion and to validate that
 * resources such as streams are freed (ie closed).
 */

public final class SimpleDoc implements Doc {

  private DocFlavor flavor;
  private DocAttributeSet attributes;
  private Object printData;
  private Reader reader;
  private InputStream inStream;

  /**
   * Constructs a <code>SimpleDoc</code> with the specified
   * print data, doc flavor and doc attribute set.
   *
   * @param printData the print data object
   * @param flavor the <code>DocFlavor</code> object
   * @param attributes a <code>DocAttributeSet</code>, which can be <code>null</code>
   * @throws IllegalArgumentException if <code>flavor</code> or <code>printData</code> is
   * <code>null</code>, or the <code>printData</code> does not correspond to the specified doc
   * flavor--for example, the data is not of the type specified as the representation in the
   * <code>DocFlavor</code>.
   */
  public SimpleDoc(Object printData,
      DocFlavor flavor, DocAttributeSet attributes) {

    if (flavor == null || printData == null) {
      throw new IllegalArgumentException("null argument(s)");
    }

    Class repClass = null;
    try {
      String className = flavor.getRepresentationClassName();
      sun.reflect.misc.ReflectUtil.checkPackageAccess(className);
      repClass = Class.forName(className, false,
          Thread.currentThread().getContextClassLoader());
    } catch (Throwable e) {
      throw new IllegalArgumentException("unknown representation class");
    }

    if (!repClass.isInstance(printData)) {
      throw new IllegalArgumentException("data is not of declared type");
    }

    this.flavor = flavor;
    if (attributes != null) {
      this.attributes = AttributeSetUtilities.unmodifiableView(attributes);
    }
    this.printData = printData;
  }

  /**
   * Determines the doc flavor in which this doc object will supply its
   * piece of print data.
   *
   * @return Doc flavor.
   */
  public DocFlavor getDocFlavor() {
    return flavor;
  }

  /**
   * Obtains the set of printing attributes for this doc object. If the
   * returned attribute set includes an instance of a particular attribute
   * <I>X,</I> the printer must use that attribute value for this doc,
   * overriding any value of attribute <I>X</I> in the job's attribute set.
   * If the returned attribute set does not include an instance
   * of a particular attribute <I>X</I> or if null is returned, the printer
   * must consult the job's attribute set to obtain the value for
   * attribute <I>X,</I> and if not found there, the printer must use an
   * implementation-dependent default value. The returned attribute set is
   * unmodifiable.
   *
   * @return Unmodifiable set of printing attributes for this doc, or null to obtain all attribute
   * values from the job's attribute set.
   */
  public DocAttributeSet getAttributes() {
    return attributes;
  }

  /*
   * Obtains the print data representation object that contains this doc
   * object's piece of print data in the format corresponding to the
   * supported doc flavor.
   * The <CODE>getPrintData()</CODE> method returns an instance of
   * the representation class whose name is given by
   * {@link DocFlavor#getRepresentationClassName() getRepresentationClassName},
   * and the return value can be cast
   * from class Object to that representation class.
   *
   * @return  Print data representation object.
   *
   * @exception  IOException if the representation class is a stream and
   *     there was an I/O error while constructing the stream.
   */
  public Object getPrintData() throws IOException {
    return printData;
  }

  /**
   * Obtains a reader for extracting character print data from this doc.
   * The <code>Doc</code> implementation is required to support this
   * method if the <code>DocFlavor</code> has one of the following print
   * data representation classes, and return <code>null</code>
   * otherwise:
   * <UL>
   * <LI> <code>char[]</code>
   * <LI> <code>java.lang.String</code>
   * <LI> <code>java.io.Reader</code>
   * </UL>
   * The doc's print data representation object is used to construct and
   * return a <code>Reader</code> for reading the print data as a stream
   * of characters from the print data representation object.
   * However, if the print data representation object is itself a
   * <code>Reader</code> then the print data representation object is
   * simply returned.
   * <P>
   *
   * @return a <code>Reader</code> for reading the print data characters from this doc. If a reader
   * cannot be provided because this doc does not meet the criteria stated above, <code>null</code>
   * is returned.
   * @throws IOException if there was an I/O error while creating the reader.
   */
  public Reader getReaderForText() throws IOException {

    if (printData instanceof Reader) {
      return (Reader) printData;
    }

    synchronized (this) {
      if (reader != null) {
        return reader;
      }

      if (printData instanceof char[]) {
        reader = new CharArrayReader((char[]) printData);
      } else if (printData instanceof String) {
        reader = new StringReader((String) printData);
      }
    }
    return reader;
  }

  /**
   * Obtains an input stream for extracting byte print data from
   * this doc.
   * The <code>Doc</code> implementation is required to support this
   * method if the <code>DocFlavor</code> has one of the following print
   * data representation classes; otherwise this method
   * returns <code>null</code>:
   * <UL>
   * <LI> <code>byte[]</code>
   * <LI> <code>java.io.InputStream</code>
   * </UL>
   * The doc's print data representation object is obtained.  Then, an
   * input stream for reading the print data
   * from the print data representation object as a stream of bytes is
   * created and returned.
   * However, if the print data representation object is itself an
   * input stream then the print data representation object is simply
   * returned.
   * <P>
   *
   * @return an <code>InputStream</code> for reading the print data bytes from this doc.  If an
   * input stream cannot be provided because this doc does not meet the criteria stated above,
   * <code>null</code> is returned.
   * @throws IOException if there was an I/O error while creating the input stream.
   */
  public InputStream getStreamForBytes() throws IOException {

    if (printData instanceof InputStream) {
      return (InputStream) printData;
    }

    synchronized (this) {
      if (inStream != null) {
        return inStream;
      }

      if (printData instanceof byte[]) {
        inStream = new ByteArrayInputStream((byte[]) printData);
      }
    }
    return inStream;
  }

}
